The invention relates to a device for guiding daylight comprising a prism plate of synthetic glass which has a base side and an active side. The active side has embankments which form trenches thereat.
Since large-area (for example 40.times.40 cm) and relatively thick (for example 5 mm) prismatic panes of synthetic glass (for example of polymethylmethacrylate-PMMA) have not yet been successfully manufactured in planar and warp-free fashion with adequate precision, such prism plates had to be composed of small sub-plates. For this purpose, the sub-plates were flued to one another at their narrow edge sides at their end faces. This, however, results in high manufacturing expense. Furthermore, the glue causes disturbing deposits and deteriorates the mechanical stability over the long term (crack formation) when such prism plates are situated in a closed interior between panes of glass.